This invention relates generally to the art of collapsible containers and more specifically to collapsible containers for medical use or for use as dispensers of other types of material.
Although the volume of packaging is important for most containers, it is especially crucial for containers of drugs, or other medicinal materials which are often delivered in containers housing specific dosages. When a container houses a specific dosage, it is important that substantially the entire amount of material be ejected from the container so that one can be sure that a proper dosage has been administered. Also, many materials, especially medicines are expensive; thus, it is important that as much medicine as possible is ejected from a container to avoid waste and undue expense.
U.S. Pat. No. 3,506,163 to Rauh et al describes a collapsible container having a protuberance extending inwardly from a bottom end thereof for being inserted into a neck of the container when it is collapsed to displace material from the neck. Although the Rauh et al device has some advantages, it is disadvantageous in that the protuberance takes up interior space of the container. Thus, it is an object of this invention to provide a collapsible container which can be collapsed to eject substantially all of the materials in a container, but yet which does not unduly limit the interior space thereof.
Another difficulty with the device of U.S. Pat. No. 3,506,163 to Rauh et al is that although the protuberance appears to fit into an interior space of the neck, it does not especially eject material positioned between the protuberance and bellows portions of the container. Thus, it is also an object of this invention to provide a collapsible container which, when it is fully collapsed, ejects substantially all material from an interior space of the container.
A difficulty with most prior-art collapsible containers not constructed of malleable material is that they tend to "spring-back" into their pre-collapsed configurations due to an "elastic memory" of sidewalls thereof. Not only does this "springing back" make it difficult to fully empty such a container, but it also causes backwashing, or sucking of ejected material back into the container and the sucking of air, or other proximate debris which may contaminate undispensed material in the container. Thus, it is an object of this invention to provide a collapsible container not constructed of a malleable material which can steadily dispense contained material in incremental amounts while progressively emptying and collapsing without the container springing back.
It is a further object of this invention to provide a collapsible container fulfilling the objects mentioned above which is relatively inexpensive to construct and easy to use.